1. Field of the Invention
The present invention relates to a variable resistor for use in various electronic components.
2. Description of the Related Art
A conventional variable resistor is disclosed in Japanese Unexamined Patent Application Publication No. 2001-15308. As shown in FIG. 11A, this variable resistor includes an insulating substrate 51 having a substantially semi-circular resistor 58 provided on the surface and a sliding contact 56 rotatably attached to the insulating substrate 51.
Into the insulating substrate 51, metallic terminals 52 and 53 are insert-molded. The sliding contact 56 includes a driver plate 56b rotationally operated by a tool, such as a screwdriver, and a body formed by folding the driver plate 56b from the external edge to the backside. The body includes a contact arm 56a sliding over the resistor 58 and a disk section 56c supporting the contact arm 56a. The sliding contact 56 is rotatably attached to the insulating substrate 51 by caulking the disk section 56c. 
A conventional variable resistor having a ceramic substrate as the insulating substrate is disclosed in Japanese Unexamined Application Publication No. 2002-231512.
Previously, the variable resistors disclosed in Japanese Unexamined Application Publication No. 2001-15308 and Japanese Unexamined Application Publication No. 2002-231512 have been required to reduce the height thereof, and to reduce the height, the height of the disk section 56c of the sliding contact 56 is reduced.
However, as shown in FIG. 11B, if only the height of the disk section 56c is reduced, the gap d between the top surface of the insulating substrate 51 and the sliding contact 56 is reduced. That is, the gap t between the contact arm 56a and the driver plate 56b is reduced. Therefore, a contact 56d of the contact arm 56a is likely to contact the driver plate 56b due to manufacturing errors or deflection in use. When the contact arm 56a is brought into contact with the driver plate 56b, the contact pressure of the contact 56d to the rotator 58 is changed, which results in fluctuations of the characteristics thereof (variations in resistance). If the contact 56d contacts the rotator 58 with a large amount of pressure, the rotator 58 may be damaged.